In recent years, there have been increasing demands for global environmental conservation. Sealed compressors for use in electric refrigerator-freezers for household uses, other refrigeration units, etc. are required to have a higher efficiency.
To address such an increase in the energy efficiency, there is known a sealed compressor including a first suction muffler and a second suction muffler provided to surround the first suction muffler (see e.g., Patent Literature 1). Hereinafter, the sealed compressor disclosed in Patent Literature 1 will be described with reference to FIGS. 4 and 5.
FIG. 4 is a cross-sectional view showing a schematic configuration of the sealed compressor disclosed in Patent Literature 1. FIG. 5 is a cross-sectional view showing a schematic configuration of a suction muffler of the sealed compressor of FIG. 4. In FIG. 4, upper and lower sides in FIG. 4 are upper and lower sides of the sealed compressor.
Firstly, the configuration of the sealed compressor disclosed in Patent Literature 1 will be described with reference to FIG. 4.
As shown in FIG. 4, the sealed compressor disclosed in Patent Literature 1 includes a sealed container 1 and a compressor body 5. In an interior of the sealed container 1, a refrigerant gas 3 is filled, and the compressor body 5 is elastically supported on the sealed container 1 by a suspension ring (not shown). The compressor body 5 includes an electric component 7 and a compression component 9 disposed below the electric component 7.
The electric component 7 includes a stator 11 and a rotor 13. The compression component 9 includes a block 17 defining a cylinder 15, a piston 19 which is reciprocatable within the cylinder 15, a valve plate 21 which closes an end surface of the cylinder 15, a cylinder head 23 covering the valve plate 21, a suction muffler 25, a crankshaft 31 having an eccentric shaft 27 and a main shaft 29, and a joining means 33 for joining the eccentric shaft 27 and the piston 19 to each other.
A compression chamber 35 is defined by the cylinder 15, the valve plate 21, and the piston 19. The suction muffler 25 is retained between the valve plate 21 and the cylinder head 23.
Next, the suction muffler 25 of the sealed compressor disclosed in Patent Literature 1 will be described in detail, with reference to FIG. 5.
As shown in FIG. 5, the suction muffler 25 includes a first suction muffler 37, a muffler entrance passage 39, which is in communication with the first suction muffler 37, a muffler exit passage 41 having an end which opens in an interior of the first suction muffler 37, a second suction muffler 45 provided to surround the first suction muffler 37, and a communication passage 47 for communicating the muffler exit passage 41 and the second suction muffler 45 with each other. In this structure, the first suction muffler 37 is thermally insulated by a wall surface of the second suction muffler 45 and by the refrigerant gas staying in a space 43 between the first suction muffler 37 and the second suction muffler 45.
Because of this structure, in the sealed compressor disclosed in Patent Literature 1, it is possible to suppress the low-temperature refrigerant gas flowing through the first suction muffler 37 from being heated by the high-temperature refrigerant gas in the interior of the sealed container 1.